Disk brake



Sept. 23, 1941. E. R. PIERCE ET AL DISK BRAKE Filed Jun' 5, 1939 2 Sheets-Sheet l v Z'Snnentors f aw 2% a .P% Y .5

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D I S K BRAKE Filed June 5, 1939 2SheetsShee t 2 Patented Sept; 23, 1941 ore Application .liune 5, 1939, Serial No. 273,40? 12 Claims. (Cl. 188-72) This invention relates to brakes and particularly to disk brakes for checking the travel of yehicles.

An object of the invention is to provide a disk brake assembly in which the applying mechanism requires minimum effort to obtain efiective braking.

Other advantages will appear from a reading of the description which follows.

On the accompanying drawings:

Figure 1 is a transverse section through the novelbrake mechanism,- the section being on line l-lof Figure 2.

Figure 2 is a view in elevation, partly broken away.

Figure 3 is a section on line 3-3 of Figure 1.

Figure l is a transverse section of a slightly modified form. t

Figure 5 is a section .on line 5-5 of Figure 4.

Figure 6 is a transverse section of another form, and

Figure 7 is a view as seen from line 'l--'i of Figure 6.

Referring by numerals to the drawings, an axle housing is identified by numeral H, the rotating axle within the housing being marked i3. Between the axle and the housing is a conventional bearing l5 shown in elevation. To better illustrate the invention the wheel is omitted. It is secured to the flange ll of the rotating axle by suitable studs such as l9. To a flange 2| of the fixed axle II is secured by a plurality of fastening means 23 a housing designated as a whole by numeral 25. This housing includes a member 21 and a mating member 29, the members secured together by fastening means 3|. These two members are provided with cooling fins marked 33 and 35. Members 21 and 28' have annular surfaces 31 and 39 respectively and engaging frictional facings 4| and 43 are carried by pressure disks 45 and M. Disk 45 is mounted to slide axially relative to and to rotate with axle I3. This sort of support is provided by apertures in the disk 45 through which extend guiding pins 49 on the inner ends of studs Iii. Disk 41 is centralized by being mounted upon an annular shoulder 58 of mem-' ber 45. It therefore may move axially and it may rotate to a limited extent upon shoulder 5i.

Secured in any convenient way to the fixed housing 2? at one point in its circular wall is a motor unit or wheel cylinder 53 which cylinder constitutes a part of a hydraulic brake system. I It employs a sealing diaphragm 55 held in position at its periphery by anchoring means,

the latter being positioned by snap ring El. The

flange til on an inner cylinder 59. Reciprocable within cylinder W is a piston 68. The plunger 63 carrying a disk 65 is normally projected towardthe brake release position by a spring till seated against the disk 65 and against the adjacent wall of member ii. The plunger extends through an opening in this wall as shown in Figure 1. The plunger operates against the suitable friction facing it carried by member ll on the side thereof remote from facing 53. Hydraulic medium is admitted to the cylinder through opening H from a conventional master cylinder. it is a normally plugged air vent.

At a plurality of circumferentially distributed positions the members id and M have opposed notches E5 to receive toothshaped lugs ll of disk expanding cams is which cams have round? ed surfaces Bl between their .ends 83 and the lugs El. These may be described as cams of such shape that relative angular motion of pressure disks 55 and 47 produce acorresponding spreading of thedisks. Such cams will have fiats'as shown on Figure 8 which provides the consequent detent action restoring the disks to their full-release position.

The operation of the brake mechanism is evident but may be briefly explained. Members 21 and 29 are held from rotation as'explained above, while the disks 46 and ll rotate with the axle l3 and the wheel, the attachment bein made by the pins'49 passing through openings in the member 65. In applying the brake, the plunger 63 is moved to the left. It pushes disk 41 into contact with friction surface 39 of the housing. The engagement of the rotating disk with the stationary housing produces a. relative rotation betwebn the two disks. The effect of such rotation may best be. appreciated by reference to Figure 3. It will be seen that the rela- 1 tive movement referred to operates through the instrumentality of the surfaces of the cams to spread the disks apart into engagement with the corresponding friction surfaces of the nonrotatable housing. In so operating, inasmuch as the friction occurs between the housing faces and the friction facings carried by the members 45 and 4? and for the reason that these friction facings are poor conductors of heat, the friction produced heat is transmitted through the wallsof the housing and the radiating fins 33 and 35 assist in carrying it away.

In Figures 4: and 5 is shown a similar arrange= ment wherein the fixedly anchored housing is marked 25' and is made up of two members 21' and 29'. The diaphragm 55' is secured substantially as in Figure 1. In this case the cylinder 59' is secured to member 21. In this form of the invention there is used a. cam 19' having a rounded part I6 seated in a correspondingly shaped recess of member 45'. It has a tooth like lug 11' in a recess of member 41. As the cam is moved by a movement of 45 relative to 41 the rounded part I6 rocks in the recess and one or the other of the rounded surfaces 8|" spreads the members 45' and 41' apart and into contact with the walls of the housing as before. It will be evident that the device functions sub.- stantially as does-the cam shown in Figure 3 which is a preferred construction.

In Figures 6 and '7 is an arrangement where a housing is formed by securing together members IIII and I03 by fastening means I05. In

are fixedly related to the axle housing being carried by an anchor plate II secured as at-I I! to a flange II9 of the axle housing. Between the disks I09 and III are spreading cams IZI which may be like those of Figure 3 or of Figure 5 or of any other form preferred. Any cocking of the plate operated by the off-center wheel cylinder is corrected by the symmetrically disposed cams. In this form the hydraulic wheel motor includes an outer cylinder I23 secured to disk I09. An inner cylinder I25 the flange of which is anchored to cylinder I23 by a snap ring I21 serves to grip the marginal edge of a diaphragm I23. The piston- I3I slidable in cylinder I25 pushes by means of a push rod I33 the disk III against the cooperating wall of a rotatable housing. Push-rod I33 may have the shape of a sector such that rotation of disk (I) will not efiectively change the distance from piston I3I to disk (I). Slight rotation of disk III with the housing and relative to disk I09 operates through the cams III to spread both disks as before and thereby check the rotation of the wheel.

In each embodiment there is a housing having opposit parallel walls with inner frictional surfaces between which are disks adapted to engage these surfaces. In eachcase a hydraulic motor located at some convenient position adjacent'the circumference of the housing causes one of the disks to engage its cooperating housing surface and in each case the cams between the disks then spread the disks into frictional contact. In this way a slight manual effort is supplemented by a servo mechanism in consequence of which powerful braking is effected.

We claim 1. In a brake, a rotating member, a member adjacent thereto fixed. from rotation, first fric-- of said disks, and a single motor means only, said motor means being positioned at one point about the circumference of the device and operably associated with one only of said disks and spaced from said cams and operable to move said one disk into contact with its cooperating wall to produce such relative rotation.

2..Ihe invention defined by claim 1, said first friction means being a housing. the internal surfaces of its walls being engaged by said discs. 3. The invention defined by claim 1, said walls being externally exposed to the air and said disks having non-conducting friction facings whereby developed heat is transmitted through said walls. 4. The invention defined by claim 1, said motor means being secured to one of said friction means.

5. The invention defined by claim 1, said m0- tor means being secured to the first mentioned friction means.

6. The invention defined by claim 1, said motor means being carried by said anchored disk.

7. In a brake, a first and rotating member, a second member adjacent thereto and held from rotation, first friction means having spaced parallel'walls, said first friction means being secured to said second member, a second friction means comprising axially reciprocable disks between and adapted to be moved to engage said spaced walls,

- means whereby one'of said discs is held from rotation relative to the first member, the other disk having limited rotation relative to the first, cam means between said discs and motor means carried by the first friction means operable to move said other disk into contact with the adjacent wall.

8. The invention defined by claim '7, said disks having notches upon adjacent edges and said cams having lugs received therein, said cams having rounded surfaces on each side of one of said lugs and operable to spread said disks.

9. Theinvention defined by claim 7, said disks having notches and said cams having lugs received therein, rounded surfaces on said cams to spread said disks in response to cam rotation and flats on said cams to predetermine the idle position of said disks.

10. The invention defined by claim 1, said motor means including a fluid chamber, a movable seal closing said chamber, a plunger moved by said seal and a member between said plunger and the said disk, said member. having a part of arcuate shape to engage said disk.

11. In a brake, a first and rotating member, a second member adjacent thereto and held from rotation, first friction means having spaced parallel walls, said first friction means being secured to said first member, a. second friction means comprising axially reciprocable disks between and adapted to engage said walls, means whereby one of'said discs is anchored from rotation relative to the second member, the other disk having limited rotation relative to the first, cam means between and operable to spread said disks and motor means carried by the anchored disk and operable to move the unanchored disk into contact with the adjacent wall, said disks having notches upon adjacent edges and said cams having rounded surfaces engaging said disks and lugs adapted to be received within said notches.

12. In a brake, a first and rotating member. a

second member adjacent thereto and held from rotation; first friction means having spaced parallel walls, said first friction means being secured adapted to engage said walls, means whereby one of said disks is anchored from rotation relative to the second member, the other disk having limited rotation relativeto the first, cam means be- I tween and operable to spread said disks and motor means carried by the anchored disk and operable to move the unanchored disk into contact and said cams having lugs received within said notches, rounded surfaces between saidilugs and the extremities thereof and flats between said rounded surfaces and saidlugs.

EARL R. PIERCE.

GILBERT K. HAUSE. 

